Canon are developing their own RAW codec for 2K and 4K video. In a patent filed in July 2010 and published yesterday, Canon describe a codec which stores raw sensor data from a 12bit high resolution RGB sensor with Bayer colour filter array.
The inventor is listed as Siu-Kei Tin (Milpitas, CA) for Canon.
It seems Canon intend to use CF card as the recording format for the RAW codec rather than SSD drives, so it could well be destined for a DSLR as well as any C300 successor.
Canon describe 4096 x 2048 RAW video at 12bit / 30fps as having a data rate of 2.8125 Gib/sec which is ‘too high for CF cards’.
Unlike uncompressed RAW, Canon’s RAW codec would reduce this data rate (whilst maintaining image quality).
From the patent –
“One trend in video capture is high definition capture. In this regard, the acquisition format is not necessarily the same as the delivery format. For an example in acquisition format, movie cameras can often support 4K capture or higher”
“As such, there are trends to support high resolution and high frame rate for video capture. By using raw sensor data output, however, data transfer rate and storage capacity of recording mediums can be limiting factors. Accordingly, there is a desire to output raw sensor data with reduced data transfer rate.”
“One conventional solution that has been implemented in some camera products is to use a form of data compression. Unlike rendered RGB data (e.g., sRGB), however, linear light sensor data may not be amenable to well known compression algorithms such as H.264 (MPEG-4 AVC) or VC-1 (SMPTE 421M). Further, such compression generally introduces artifacts to the camera raw data, and these artifacts may be difficult to fix in the post-production. Thus, there may be a practical implication that, when shooting at high resolution such as 4K, one is limited to lower frame rate, such as 24 fps.”
“Disclosed [patent]describe devices and methods for recording successive frames of raw sensor data depicting a moving scene.”
The patent also describes a high resolution RGB sensor and colour filter array ‘which can correspond to a Bayer pattern’. Both DSLRs and the C300 use this sensor technology.
Thank you to EOSHD forum member Tungah for drawing this to our attention
PS
Maybe this is the testbed?
